// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <vector>

#include "base/at_exit.h"
#include "base/base_paths.h"
#include "base/bind.h"
#include "base/command_line.h"
#include "base/files/file_path.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/native_library.h"
#include "base/path_service.h"
#include "base/strings/stringprintf.h"
#include "base/threading/thread_restrictions.h"
#include "base/trace_event/trace_event.h"
#include "base/win/windows_version.h"
// TODO(jmadill): Apply to all platforms eventually
#include "ui/gl/angle_platform_impl.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_context_stub_with_extensions.h"
#include "ui/gl/gl_egl_api_implementation.h"
#include "ui/gl/gl_gl_api_implementation.h"
#include "ui/gl/gl_implementation.h"
#include "ui/gl/gl_osmesa_api_implementation.h"
#include "ui/gl/gl_surface_wgl.h"
#include "ui/gl/gl_wgl_api_implementation.h"

#if defined(ENABLE_SWIFTSHADER)
#include "software_renderer.h"
#endif

namespace gfx {

namespace {

    const wchar_t kD3DCompiler[] = L"D3DCompiler_47.dll";

    void GL_BINDING_CALL MarshalClearDepthToClearDepthf(GLclampd depth)
    {
        glClearDepthf(static_cast<GLclampf>(depth));
    }

    void GL_BINDING_CALL MarshalDepthRangeToDepthRangef(GLclampd z_near,
        GLclampd z_far)
    {
        glDepthRangef(static_cast<GLclampf>(z_near), static_cast<GLclampf>(z_far));
    }

    bool LoadD3DXLibrary(const base::FilePath& module_path,
        const base::FilePath::StringType& name)
    {
        base::NativeLibrary library = base::LoadNativeLibrary(base::FilePath(name), NULL);
        if (!library) {
            library = base::LoadNativeLibrary(module_path.Append(name), NULL);
            if (!library) {
                DVLOG(1) << name << " not found.";
                return false;
            }
        }
        return true;
    }

    // TODO(jmadill): Apply to all platforms eventually
    base::LazyInstance<ANGLEPlatformImpl> g_angle_platform_impl = LAZY_INSTANCE_INITIALIZER;

    ANGLEPlatformShutdownFunc g_angle_platform_shutdown = nullptr;

} // namespace

void GetAllowedGLImplementations(std::vector<GLImplementation>* impls)
{
    impls->push_back(kGLImplementationEGLGLES2);
    impls->push_back(kGLImplementationDesktopGL);
    impls->push_back(kGLImplementationOSMesaGL);
}

bool InitializeStaticGLBindings(GLImplementation implementation)
{
    // Prevent reinitialization with a different implementation. Once the gpu
    // unit tests have initialized with kGLImplementationMock, we don't want to
    // later switch to another GL implementation.
    DCHECK_EQ(kGLImplementationNone, GetGLImplementation());

    // Allow the main thread or another to initialize these bindings
    // after instituting restrictions on I/O. Going forward they will
    // likely be used in the browser process on most platforms. The
    // one-time initialization cost is small, between 2 and 5 ms.
    base::ThreadRestrictions::ScopedAllowIO allow_io;

    switch (implementation) {
    case kGLImplementationOSMesaGL: {
        base::FilePath module_path;
        PathService::Get(base::DIR_MODULE, &module_path);
        base::NativeLibrary library = base::LoadNativeLibrary(
            module_path.Append(L"osmesa.dll"), NULL);
        if (!library) {
            PathService::Get(base::DIR_EXE, &module_path);
            library = base::LoadNativeLibrary(
                module_path.Append(L"osmesa.dll"), NULL);
            if (!library) {
                DVLOG(1) << "osmesa.dll not found";
                return false;
            }
        }

        GLGetProcAddressProc get_proc_address = reinterpret_cast<GLGetProcAddressProc>(
            base::GetFunctionPointerFromNativeLibrary(
                library, "OSMesaGetProcAddress"));
        if (!get_proc_address) {
            DLOG(ERROR) << "OSMesaGetProcAddress not found.";
            base::UnloadNativeLibrary(library);
            return false;
        }

        SetGLGetProcAddressProc(get_proc_address);
        AddGLNativeLibrary(library);
        SetGLImplementation(kGLImplementationOSMesaGL);

        InitializeStaticGLBindingsGL();
        InitializeStaticGLBindingsOSMESA();
        break;
    }
    case kGLImplementationEGLGLES2: {
        base::FilePath module_path;
        if (!PathService::Get(base::DIR_MODULE, &module_path))
            return false;

        // Attempt to load the D3DX shader compiler using the default search path
        // and if that fails, using an absolute path. This is to ensure these DLLs
        // are loaded before ANGLE is loaded in case they are not in the default
        // search path.
        LoadD3DXLibrary(module_path, kD3DCompiler);

        base::FilePath gles_path;
        const base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
        bool using_swift_shader = command_line->GetSwitchValueASCII(switches::kUseGL) == kGLImplementationSwiftShaderName;
        if (using_swift_shader) {
            if (!command_line->HasSwitch(switches::kSwiftShaderPath))
                return false;
            gles_path = command_line->GetSwitchValuePath(switches::kSwiftShaderPath);
            // Preload library
            LoadLibrary(L"ddraw.dll");
        } else {
            gles_path = module_path;
        }

        // Load libglesv2.dll before libegl.dll because the latter is dependent on
        // the former and if there is another version of libglesv2.dll in the dll
        // search path, it will get loaded instead.
        base::NativeLibrary gles_library = base::LoadNativeLibrary(
            gles_path.Append(L"libglesv2.dll"), NULL);
        if (!gles_library) {
            DVLOG(1) << "libglesv2.dll not found";
            return false;
        }

        // When using EGL, first try eglGetProcAddress and then Windows
        // GetProcAddress on both the EGL and GLES2 DLLs.
        base::NativeLibrary egl_library = base::LoadNativeLibrary(
            gles_path.Append(L"libegl.dll"), NULL);
        if (!egl_library) {
            DVLOG(1) << "libegl.dll not found.";
            base::UnloadNativeLibrary(gles_library);
            return false;
        }

#if defined(ENABLE_SWIFTSHADER)
        if (using_swift_shader) {
            SetupSoftwareRenderer(gles_library);
        }
#endif

        if (!using_swift_shader) {
            // Init ANGLE platform here, before we call GetPlatformDisplay().
            // TODO(jmadill): Apply to all platforms eventually
            ANGLEPlatformInitializeFunc angle_platform_init = reinterpret_cast<ANGLEPlatformInitializeFunc>(
                base::GetFunctionPointerFromNativeLibrary(
                    gles_library,
                    "ANGLEPlatformInitialize"));
            if (angle_platform_init) {
                angle_platform_init(&g_angle_platform_impl.Get());

                g_angle_platform_shutdown = reinterpret_cast<ANGLEPlatformShutdownFunc>(
                    base::GetFunctionPointerFromNativeLibrary(
                        gles_library,
                        "ANGLEPlatformShutdown"));
            }
        }

        GLGetProcAddressProc get_proc_address = reinterpret_cast<GLGetProcAddressProc>(
            base::GetFunctionPointerFromNativeLibrary(
                egl_library, "eglGetProcAddress"));
        if (!get_proc_address) {
            LOG(ERROR) << "eglGetProcAddress not found.";
            base::UnloadNativeLibrary(egl_library);
            base::UnloadNativeLibrary(gles_library);
            return false;
        }

        SetGLGetProcAddressProc(get_proc_address);
        AddGLNativeLibrary(egl_library);
        AddGLNativeLibrary(gles_library);
        SetGLImplementation(kGLImplementationEGLGLES2);

        InitializeStaticGLBindingsGL();
        InitializeStaticGLBindingsEGL();

        // These two functions take single precision float rather than double
        // precision float parameters in GLES.
        ::gfx::g_driver_gl.fn.glClearDepthFn = MarshalClearDepthToClearDepthf;
        ::gfx::g_driver_gl.fn.glDepthRangeFn = MarshalDepthRangeToDepthRangef;
        break;
    }
    case kGLImplementationDesktopGL: {
        base::NativeLibrary library = base::LoadNativeLibrary(
            base::FilePath(L"opengl32.dll"), NULL);
        if (!library) {
            DVLOG(1) << "opengl32.dll not found";
            return false;
        }

        GLGetProcAddressProc get_proc_address = reinterpret_cast<GLGetProcAddressProc>(
            base::GetFunctionPointerFromNativeLibrary(
                library, "wglGetProcAddress"));
        if (!get_proc_address) {
            LOG(ERROR) << "wglGetProcAddress not found.";
            base::UnloadNativeLibrary(library);
            return false;
        }

        SetGLGetProcAddressProc(get_proc_address);
        AddGLNativeLibrary(library);
        SetGLImplementation(kGLImplementationDesktopGL);

        // Initialize GL surface and get some functions needed for the context
        // creation below.
        if (!GLSurfaceWGL::InitializeOneOff()) {
            LOG(ERROR) << "GLSurfaceWGL::InitializeOneOff failed.";
            return false;
        }
        wglCreateContextProc wglCreateContextFn = reinterpret_cast<wglCreateContextProc>(
            GetGLProcAddress("wglCreateContext"));
        wglDeleteContextProc wglDeleteContextFn = reinterpret_cast<wglDeleteContextProc>(
            GetGLProcAddress("wglDeleteContext"));
        wglMakeCurrentProc wglMakeCurrentFn = reinterpret_cast<wglMakeCurrentProc>(
            GetGLProcAddress("wglMakeCurrent"));

        // Create a temporary GL context to bind to entry points. This is needed
        // because wglGetProcAddress is specified to return NULL for all queries
        // if a context is not current in MSDN documentation, and the static
        // bindings may contain functions that need to be queried with
        // wglGetProcAddress. OpenGL wiki further warns that other error values
        // than NULL could also be returned from wglGetProcAddress on some
        // implementations, so we need to clear the WGL bindings and reinitialize
        // them after the context creation.
        HGLRC gl_context = wglCreateContextFn(GLSurfaceWGL::GetDisplayDC());
        if (!gl_context) {
            LOG(ERROR) << "Failed to create temporary context.";
            return false;
        }
        if (!wglMakeCurrentFn(GLSurfaceWGL::GetDisplayDC(), gl_context)) {
            LOG(ERROR) << "Failed to make temporary GL context current.";
            wglDeleteContextFn(gl_context);
            return false;
        }

        InitializeStaticGLBindingsGL();
        InitializeStaticGLBindingsWGL();

        wglMakeCurrent(NULL, NULL);
        wglDeleteContext(gl_context);

        break;
    }
    case kGLImplementationMockGL: {
        SetGLImplementation(kGLImplementationMockGL);
        InitializeStaticGLBindingsGL();
        break;
    }
    default:
        return false;
    }

    return true;
}

bool InitializeDynamicGLBindings(GLImplementation implementation,
    GLContext* context)
{
    switch (implementation) {
    case kGLImplementationOSMesaGL:
    case kGLImplementationEGLGLES2:
    case kGLImplementationDesktopGL:
        InitializeDynamicGLBindingsGL(context);
        break;
    case kGLImplementationMockGL:
        if (!context) {
            scoped_refptr<GLContextStubWithExtensions> mock_context(
                new GLContextStubWithExtensions());
            mock_context->SetGLVersionString("3.0");
            InitializeDynamicGLBindingsGL(mock_context.get());
        } else
            InitializeDynamicGLBindingsGL(context);
        break;
    default:
        return false;
    }

    return true;
}

void InitializeDebugGLBindings()
{
    InitializeDebugGLBindingsEGL();
    InitializeDebugGLBindingsGL();
    InitializeDebugGLBindingsOSMESA();
    InitializeDebugGLBindingsWGL();
}

void ClearGLBindings()
{
    // TODO(jmadill): Apply to all platforms eventually
    if (g_angle_platform_shutdown) {
        g_angle_platform_shutdown();
    }

    ClearGLBindingsEGL();
    ClearGLBindingsGL();
    ClearGLBindingsOSMESA();
    ClearGLBindingsWGL();
    SetGLImplementation(kGLImplementationNone);
    UnloadGLNativeLibraries();
}

bool GetGLWindowSystemBindingInfo(GLWindowSystemBindingInfo* info)
{
    switch (GetGLImplementation()) {
    case kGLImplementationDesktopGL:
        return GetGLWindowSystemBindingInfoWGL(info);
    case kGLImplementationEGLGLES2:
        return GetGLWindowSystemBindingInfoEGL(info);
    default:
        return false;
    }
}

} // namespace gfx
